1. Field of the Invention
The present invention relates to a structure of a cooling device for an image forming apparatus of an electrostatic photography type mounted in a copying machine, a facsimile or a laser printer, for example.
2. Description of Related Art
A conventional image forming apparatus of this type is provided with a paper feed unit that feeds paper for the formation of an image, a processing unit that incorporates therein a photosensitive drum and a developing device for forming a toner image on the photosensitive drum, an exposure unit for forming an electrostatic latent image on the photosensitive drum, a fixing unit for heat-fixing the toner image after transfer onto the paper, a drive motor for driving rotating parts used in the above units, transmission gears, and a power source for a controller. These units are mounted to a main frame formed by a metallic plate or a synthetic resin. Further mounted to the main frame is a train of gears for the transmission of power to each of the above units. A case cover is formed of a synthetic resin so as to surround the front, rear, right and left sides of all of the main frame, the gear train and the aforesaid units. The case cover is fixed to the main frame with bolts or the like, thereby constituting a body case of the image forming apparatus.
For diminishing the heat generated from the above power source, drive motor and heating-type fixing unit, a cooling fan has heretofore been attached to the inner surface of the body case so that the direction of the wind generated from the fan is substantially horizontal or vertical.
However, in the case where the foregoing heat generating sources are located away from one another and at different heights within the body case, it is difficult to make the wind from one cooling fan advance in plural directions. Therefore, it is required to dispose cooling fans respectively at positions close to the heat generating sources, thus resulting in an increase in the manufacturing cost. Besides, it becomes necessary to ensure spaces for mounting those cooling fans and this gives rise to the problem that the size of the apparatus becomes larger.